Question: Simplify the expression. $(-2r^{4}-5r^{2}+6r)(-6r^{3}-3r)$
First use the distributive property. $ - 2 r^4 (-6 r^3) - 2 r^4 (-3 r) - 5 r^2 (-6 r^3) - 5 r^2 (-3 r) + 6 r (-6 r^3) + 6 r (-3 r) $ Simplify. $ 12r^{7} + 6r^{5} + 30r^{5} + 15r^{3} - 36r^{4} - 18r^{2} $ $12r^{7}+36r^{5}-36r^{4}+15r^{3}-18r^{2}$ Identify like terms. $ { 12r^{7}} {+ 6r^{5}} {+ 30r^{5}} {+ 15r^{3}} {- 36r^{4}} {- 18r^{2}} $ Add the coefficients. $ { 12r^{7}} {+ 36r^{5}} { -36r^{4}} {+ 15r^{3}} { -18r^{2}} $